I've got a car with the option of installing 6-speakers, but of course there are only 4 output channels from the empeg/Rio Car so what is the best way to add more speakers into the mix withour getting buzzing, humming or degrading sound quality? I'm thinking of using RCA Y-splitter cables on the front left & right outputs into two separate amplifiers in the trunk so that each lead can power a dedicated speaker. Is this the way the pros would do it?

Keep in mind that, between the Empeg and the speakers, there needs to be some kind of amplification. It's the amplifier arrangement that will dictate your system design. What will the amplifier setup be like on this car and how many inputs do the amplifiers have?

(Just because there are six speakers doesn't mean there are six amplifier inputs.)

You are correct. Currently I have a Sony eXplode amp with 4 outputs so I realize that I would either need to purchase one with 6 outputs or connect a second amp. But what I'm really wondering is whether the logistics of my theory is sound (no pun intended) and if splitting the signal from the empeg preamp is the least expensive and/or best way to add more speakers into the mix.

If you're going to go with a two amplifier setup, run the Left/Right front outputs from the empeg into one of the amps, the Left/Right rear outputs from the empeg into the second amp. Use one of the amps to run your subwoofers, the other amp to the four remaining speakers. Tune/tweak your amps (crossover settings, output gain, etc.) to match the speakers they are driving.

1 ea, 10,000uF 35V mid-ESR capacitor to damp out the resonances of the charge current between the 58F Capacitor and Batteries.

It's all wired to deliver a low impedance source to the amplifier.

The design supplies both constant Power (Battery), and Constant Peak energy capacity (Capacitor), locally for the system. The idea is to supply a very low source impedance over frequency (Middlebrook criteria) to guarantee the energy is available on demand. Some devices like 10X lower source impedance than the user of that power from DC to 50kHz. Mine is in that range. You can actually damage a power amplifier by "starving" it of this energy as it requires more current to run becuase the voltage is low where it needs it.

The MC4000M has 4 separate Power Supplies. There are filters between each of the 4 supplies (Series Inductor and 2 ea 2200uF for each supply). It's a very well designed amplifier.

I use the path back to car battery (an Optima Red Top), really as a charging source for the Local Power Center in the trunk. I even sized the cable back to the car battery to make it a higher resistance path (4 AWG) to force the Local Power Center to supply the majority of the energy locally. This also protects my Alternator (I have been able to remain with a stock Alternator), as the cable will not support the high current path back to the Alternator/Battery. Only the delta voltage appears across the cable.

The rest of the system is a McIntosh MX-4000 Head Unit, the Empeg Rio (2 ea 250GB drives) of course, Boston Pro Components in the doors, Boston 3 way 6X9s in the rear deck, and 2 Infinity Kappa 1220W (more efficient than the newer ones - hard to find these) 12 inch drivers in a partitioned sealed box.

The system sounds awesome. Doesn't matter what is played from Carpenters through Led Zepplin. Needless to say, my headlights do not dim at high volumes!

Ross

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In SI, a little termination and attention to layout goes a long way. In EMC, without SI, you'll spend 80% of the effort on the last 3dB.

I take that back. You can run two speakers off the same amplifier channel, provided that you do the correct impedance matching. There's a whole system for doing this sort of thing. Basically, you end up needing twice the amplifier power than what's shown on the box (since each channel is now driving two speakers instead of one), but it works. It's a common technique. Most likely covered in detail at one of these places (if any of those old links still work).